Workpiece holder for processing apparatus, and processing apparatus using the same

ABSTRACT

An inexpensive workpiece holder having high reliability and a processing apparatus equipped with the workpiece holder are provided, in which damage caused by oxygen in the air is prevented. The holder comprises: a ceramic body which has an electrode and a heater circuit and which can holds a workpiece; a tubular member having an end portion connected to the ceramic body; a sealing member which is disposed inside the tubular member and which isolates a space inside the tubular member into two regions: a region on the first end portion (“sealed portion”) and a region on the opposite side (“opposite region”); and power supply conductive members which extend from the opposite region side, penetrating the sealing member to the sealed region side, and which are electrically connected to the electrode and the heater circuit.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a holder for retaining a material, suchas a wafer, to be processed (hereinafter referred to as “workpieceholder” or a “susceptor”), in a processing apparatus such as asemiconductor manufacturing apparatuses, and a processing apparatususing the same. In particular, the present invention relates to aworkpiece holder having superior reliability against heat cycle, and toa processing apparatus having such workpiece holder.

2. Description of the Related Art

Heretofore, in manufacturing steps of semiconductor devices,film-formation or etching treatment have been performed on workpiece,that is, semiconductor substrates. A processing apparatus for processingsuch substrates is provided with a susceptor, which is a holder forretaining a semiconductor substrate during its treatment.

A conventional susceptor described above has been disclosed in, forexample, Japanese Unexamined Patent Application Publication No.7-153706.

However, the conventional susceptor described above has such problems asdescribed below. That is, in order to supply an inert gas inside asupporting table, a gas supply tube must be provided for the susceptor,and in addition, devices necessary for supplying an inert gas, such asmass flow controller, must be connected to the gas supply tube.Consequently, the structure of the susceptor becomes complicated, and asa result, manufacturing cost of the susceptor used as a workpiece holderis increased.

In addition, when this susceptor is used, running cost of the susceptoris also increased since an inert gas must always be supplied inside thesupporting table.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an inexpensiveworkpiece holder of high reliability that can be obtained by avoidingdamage caused by reacting gases, and a processing apparatus providedwith such a workpiece holder.

A workpiece holder of the present invention comprises: a ceramic bodywhich has an electrical circuit and which can hold a workpiece; atubular member having an end portion (“first end portion”) fixed to therear surface of the ceramic body; a sealing member which is disposedinside the tubular member and bonded thereto and which separates a spaceinside the tubular member into two regions: a region on the first endportion side (“sealed region”) and a region on the opposite side(“opposite region”); and power supply conductive members which extendsfrom the opposite region side, penetrating the sealing member to thesealed region side, and which are electrically connected to theelectrical circuit of the ceramic body.

A processing apparatus of the present invention is equipped with theabove-mentioned workpiece holder.

Susceptors used in semiconductor manufacturing apparatuses are requiredto withstand severe process conditions, such as etching treatment onsemiconductor substrates, and in addition, the susceptors have beenrequired to be inexpensive. When the workpiece holder of the presentinvention is used, an inexpensive susceptor that can reliably withstandsevere process conditions can be obtained for use in a semiconductormanufacturing apparatus.

In the workpiece holder according to the present invention, since thesealing member is disposed inside the tubular member supporting theceramic body and is bonded thereto, connection portions at which theelectrical circuits for the ceramic body are connected to the powersupply conductive member can be isolated from an atmosphere around theworkpiece holder. Hence, when the workpiece holder of the presentinvention is used for processing workpieces such as substrates, theconnection portions can be prevented from being damaged by oxygencontained in the air present inside the tubular member. Therefore, it isunnecessary to supply an inert gas into the space inside the tubularmember in order to avoid such damage of the connection portions asdescribed above. This results in reduction in cost of the workpieceholder.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, cross-sectional view of a workpiece holder, whichis used in a processing apparatus, according to a first embodiment ofthe present invention;

FIG. 2 is a schematic, enlarged, cross-sectional view showing a part ofthe workpiece holder shown in FIG. 1;

FIG. 3 is a schematic, enlarged, cross-sectional view showing a part,which is different from that shown in FIG. 2, of the workpiece holdershown in FIG. 1;

FIG. 4 is a schematic, cross-sectional view of a workpiece holderaccording to a second embodiment of the present invention;

FIG. 5 is a schematic, cross-sectional view of a workpiece holderaccording to a third embodiment of the present invention;

FIG. 6 is a schematic, cross-sectional view of a workpiece holderaccording to a fourth embodiment of the present invention;

FIG. 7 is a schematic, cross-sectional view of showing a part of theholder shown in FIG. 6;

FIG. 8 is a schematic, cross-sectional view showing a first modifiedexample of the workpiece holder shown in FIGS. 6 and 7 according to thefourth embodiment of the present invention;

FIG. 9 is a schematic, cross-sectional view showing a part of theworkpiece holder shown in FIG. 8;. FIG. 10 is a schematic,cross-sectional view showing a second modified example of the workpieceholder shown in FIGS. 6 and 7 according to the fourth embodiment of thepresent invention;

FIG. 11 is a schematic, cross-sectional view showing a part of theworkpiece holder shown in FIG. 10;

FIG. 12 is a schematic, cross-sectional view of a sample used fordetermining airtightness;

FIG. 13 is a schematic, cross-sectional view of a sample used fordetermining airtightness; and

FIG. 14 is a schematic, cross-sectional view of a sample used fordetermining airtightness.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A workpiece holder in accordance with a first aspect of the presentinvention comprises: a ceramic body which has an electrical circuit andwhich is used for holding workpiece: a tubular member having an endportion (“first end portion”) bonded to the ceramic body; a sealingmember which is disposed inside the tubular member and bonded theretoand which separates a space inside the tubular member into two regions:a region on the first end portion side (“sealed region”); and a regionon the opposite side (“opposite region”); and power supply conductivemembers which extends from the opposite region side to the sealed regionside, penetrating the sealing member, and which are electricallyconnected to the electrical circuit.

The electrical circuit in the ceramic body includes, for example, aheater circuit for heating a workpiece, an electrostatic electrode forretaining the workpieces on the ceramic body, or an RF electrode forgenerating plasma. The material for forming this electrical circuit maybe low oxidation-resistance tungsten or molybdenum, etc. In addition, amaterial having low oxidation-resistance is also used in some cases fora power supply terminal used at the connection portion between theelectrical circuit and the power supply conductive member. Accordingly,if the connection portion between the power supply conductive member andthe electrical circuit or the power supply terminal is in the air, theelectrical circuit exposed in the tubular member may be corroded byoxygen which is present in the air in the case in which the workpieceholder is heated and semiconductor substrates or the like are placedthereon and etched.

However, according to the present invention, the connection portionsbetween the electrical circuit for the ceramic body and the power supplyconductive members are located in a region surrounded by the sealingmember, the tubular member, and the ceramic body (that is, the sealedregion mentioned above). If a bonding region between the tubular memberand the ceramic body and a bonding portion between the sealing memberand the ceramic body are formed so as to have predeterminedairtightness, the portion (sealed portion) in which the connectionportions described above are located is isolated from a apacesurrounding the sealed portion inside the tubular member (hereinafter,the “surrounding region”). Consequently, when a heating treatment suchas etching is performed, it is possible to prevent the electricalcircuit or a material forming the connection portion from being corrodedby oxygen present in the atmosphere inside the tubular member.

In addition, since the sealing member is disposed inside the tubularmember such that the sealed region is isolated thereby from thesurrounding region as described above, it is unnecessary to provideplumbing for supplying an inert gas into the tubular member as has beendone in a conventional apparatus. Accordingly, the structure of aworkpiece holder can be simplified, and hence the manufacturing costthereof can be reduced. In addition, when a workpiece is processed (byetching or the like) using the workpiece holder, it is not necessary tocontinuously supply an inert gas inside the tubular member, and hence,the running cost of treatment using the workpiece holder described abovecan be reduced.

Furthermore, by selecting materials having suitable thermal expansioncoefficients, which are not so different from each other, for theceramic body, the tubular member, the sealing member, and the powersupply conductive members, which constitute the workpiece holder, it ispossible to avoid a problem such as local concentration of thermalstress due to change in the atmospheric temperature. Accordingly, aworkpiece holder having high reliability against thermal hysteresis dueto heat cycle can be obtained.

In the workpiece holder in accordance with the first aspect of thepresent invention, the sealing member is preferably provided in contactwith the rear surface (opposite side of a surface on which a wafer is tobe mounted) of the ceramic body. In addition, in the workpiece holder inaccordance with the first aspect of the present invention, the sealingmember may be bonded to the surface of the ceramic body with a fixingbond member provided therebetween.

In such case, the sealing member itself need not have a large strength,since the ceramic body can support the sealing member. Accordingly, thethickness of the sealing member can be decreased. Hence, the degree offreedom of designing the sealing member can be made larger.

In the workpiece holder in accordance with the first aspect of thepresent invention, the fixing bond member may be formed by heating afixing bond material at a pressure of 100 g/cm² or more applied theretothrough the sealing member.

Accordingly, the number of minute gaps can be reduced in the fixing bondmember, and hence a bonding portion having a superior airtightness canbe obtained. In addition, the bond strength between the ceramic body andthe sealing member can be simultaneously increased. The reason thepressure applied to the fixing bond member is set to 100 g/cm² or moreis that when the pressure is 100 g/cm² or more, the airtight property ofthe fixing bond member can be increased, and when the pressure is lessthan 100 g/cm², the advantage of increase in airtight property cannot beobtained.

In the workpiece holder in accordance with the first aspect of thepresent invention, the sealing member may be disposed at a distance fromthe surface of the ceramic body.

In this case, since the sealing member is not in contact with theceramic body, it is possible to prevent the temperature distribution ofthe ceramic body. Accordingly, due to the contact of the sealing memberwith the ceramic body from becoming uneven due to the contact with thesealing member. As a result, the temperature distribution in the ceramicbody can be made more uniform, and hence the temperature distribution ina workpiece held on the ceramic body can be easily made uniform.

In the workpiece holder in accordance with the first aspect of thepresent invention, the region surrounded by the sealing member, thetubular member, and the ceramic body may be vacuum or non-oxidizingatmosphere.

In this case, oxidation of the power supply conductive members and theconnection portions between the power supply conductive members and theelectrical circuit in the region can be effectively prevented.

In the workpiece holder in accordance with the first aspect of thepresent invention, the rate of helium leak from the region surrounded bythe sealing member, the tubular member, and the ceramic body (the sealedregion) to other region may be 10⁻⁸ Pa·m³/s or less.

In this case, when the rate of helium leak in the sealed region is setto a value within the above-mentioned range, oxidation of the powersupply conductive members and the connection portions between theelectrical circuit and the power supply conductive members which arelocated in the region can be prevented without fail.

The workpiece holder in accordance with the first aspect of the presentinvention may further comprise a bond member provided at the bondingportion between the tubular member and the sealing member.

In this case, gaps at the bonding portion between the tubular member andthe sealing member can be filled with the bond member. As a result, theairtightness of the bonding portion described above can be improved.Accordingly, the first region inside the tubular member can be isolatedsecurely from an outer region surrounding the workpiece holder.

In the workpiece holder in accordance with the first aspect of thepresent invention, the bond member may have a surface extending from apart of the inside surface of the tubular member onto a part of asurface of the sealing member, and the surface of the bond memberpreferably is a concave meniscus.

When the bond member has the shape (so-called meniscus) described above,it is understood that the bond member has good wettability to thesurfaces of the sealing member and the tubular member. That is, when thebond member has such concave meniscus, the bonding portion has highairtightness. As a result, leak generation at the bonding portion can bereliably suppressed.

A workpiece holder in accordance with a second aspect of the presentinvention comprises a ceramic body which has an electrical circuit andwhich is used for holding a workpiece: a tubular member having an endportion fixed to the rear surface of the ceramic body; power supplyconductive members electrically connected to the electrical circuit atconnection portions located inside the tubular member; and sealingmembers which are disposed inside the tubular member and fixed to therear surface of the ceramic body so as to form sealed portions eachsurrounding the respective connection portions such that the sealingmembers isolate the sealed portions of the connection portions from anatmosphere surrounding the outer periphery of the sealing member.

Accordingly, the connection portions between the electrical circuit inthe ceramic body and the power supply conductive members are eachlocated in a region surrounded by the sealing member and the ceramicbody. When the bonding region between the sealing member and the ceramicbody is formed so as to have predetermined airtightness, the regions inwhich the connection portions are located are isolated from a spacesurrounding the sealing member. Consequently, when a heating treatmentsuch as etching is performed, it is possible to prevent an occurrence ofthe problem that the electrical circuit or materials forming theconnection portions are corroded by oxygen in the air present inside thetubular member.

In addition, since the sealing members are disposed inside the tubularmember, and the above-mentioned connection portions are isolated(sealed) from the region surrounding the sealing members, it isunnecessary to install plumbing for supplying an inert gas into thetubular member. Accordingly, the structure of a workpiece holder can besimplified, and hence the manufacturing cost thereof can be reduced. Inaddition, when workpieces are processed (etching or the like) using theworkpiece holder, there is no need to supply an inert gas inside thetubular member, and hence, the running cost of treatment using theworkpiece holder can be reduced.

Furthermore, by selecting materials having thermal expansioncoefficients, which are not so different from each other, for theceramic body, the tubular member, the sealing member, and the powersupply conductive member, which constitute the workpiece holder, it ispossible to avoid a problem such as local concentration of thermalstress due to change in the atmospheric temperature. Accordingly, aworkpiece holder having high reliability against heat history such asheat cycle can be realized.

In addition, since the sealing members are provided for the individualconnection portions between the electrical circuits and the power supplyconductive members, as described above, the size of each of the sealingmembers can be decreased. Accordingly, the cost of the sealing membercan be reduced. In addition, since the area in which the sealing membersare in contact with the ceramic body is decreased, the influence of thesealing member on a temperature distribution in the ceramic body can bereduced. As a result, the temperature distribution in the ceramic bodycan be made more uniform, and hence a temperature distribution in aworkpiece, which is held on the ceramic body, can be easily madeuniform.

In the workpiece holder in accordance with the second aspect of thepresent invention, the atmosphere surrounding the regions in which theconnection portions between the electrical circuits and the power supplyconductive members are located is preferably vacuum or non-oxidizingatmosphere.

In this case, oxidation of the power supply conductive member and theconnection portion between the electrical circuit and the power supplyconductive member can be effectively prevented.

In the workpiece holder in accordance with the second aspect of thepresent invention, the rate of helium leak from the region in which theconnection portion is located to other region is preferably 10⁻⁸ Pa·m³/sor less.

In this case, when the helium leak rate of the region described above isset as mentioned above, oxidation of the power supply conductive memberand the connection portion between the electrical circuit and the powersupply conductive member can be reliably suppressed.

The workpiece holder in accordance with the second aspect of the presentinvention may further comprise a bond member provided at the bondingportion between the ceramic body and the sealing member.

In this case, in the bonding portion between the ceramic body and thesealing member, gaps therebetween can be filled with the bond member. Asa result, the airtight property of the bonding portion described abovecan be improved. Accordingly, the region in which the connection portionbetween the electrical circuit and the power supply conductive member islocated can be securely isolated from the region surrounding the sealingmember.

In the workpiece holder in accordance with the first or the secondaspect of the present invention, the bond member may be formed by heattreatment of a bond material at a pressure of 100 g/cm² or more appliedthereto through the sealing member.

In this case, since the number of minute gaps can be reduced in the bondmember, a bonding portion having superior airtightness can be obtained.Accordingly, the rate of helium leak from the region surrounded by thesealing member, the tubular member, and the ceramic body to other regionin which the connection portion between the electrical circuit and thepower supply conductive member is located to other region can be reduced(that is, airtightness can be improved). In addition, the bondingstrength of the bonding portion between the tubular member and thesealing member or the bonding strength of the bonding portion betweenthe ceramic body and the sealing member can be increased. Thus, morereliable bonding portion can be obtained. The reason for setting thepressure applied to the bond material to 100 g/cm² or more is that ifthe pressure is 100 g/cm² or more, helium leak rate can be reduced, andif the pressure is less than 100 g/cm², the helium leak rate can hardlybe reduced.

In addition, in this case, the bond material may contain glass. Thisbond material containing glass may be formed beforehand by pre-firinginto a shape approximately similar to a bond member. Subsequently, thebond material thus pretreated may be disposed at a predeterminedposition and processed by heat treatment. Thus, bonding and sealing canbe easily made at the bonding portion.

In the workpiece holder in accordance with the second aspect of thepresent invention, the bond member may have a surface extending from apart of the rear surface of the ceramic body onto a part of the surfaceof the sealing member, and the surface of the bond member preferably isa concave meniscus.

In the case described above, when the bond member forms a so-calledmeniscus shape as described above, it is understood that the bond memberhas good wettability to the surfaces of the sealing member and theceramic body. That is, when the bond member has the concave meniscus,the bonding portion has high airtightness. As a result, the occurrenceof leak at the bonding portion can be securely prevented.

In the workpiece holder in accordance with the first or the secondaspect of the present invention, the bond member may include glass.

When a ceramic material is used for the bond member, the heat treatmenttemperature is increased to 1,500° C. or more in the process of formingthe bond member at the bonding portion. In this process, when thesealing member and the power supply conductive member are bondedtogether beforehand, a material capable of withstanding a hightemperature of 1,500° C. or more must be used for forming this powersupply conductive member. Therefore, the kind of material that can beused for forming the power supply conductive member is very limited.

In contrast, when glass is used for the bond member, the heat treatmenttemperature for forming the bond member at the bonding portion can bedecreased to a relatively low temperature (approximately 1,000° C. orless). Accordingly, the freedom of selecting a material for the powersupply conductive member can be increased.

In the case in which the sealing member or the tubular member is formedof ceramic, if a metal brazing material is used as a typical bondmember, thermal stress caused by heat cycle or the like may beconcentrated at the bonding portion since ceramic has a thermalexpansion coefficient smaller than that of a metal brazing material. Asa result, the bonding portion may be damaged by the thermal stress insome cases. In contrast, the thermal expansion coefficient of glass isrelatively lower than that of a metal brazing material or the like.Accordingly, when a suitable kind of glass for a bond member isselected, the thermal expansion coefficient of the bond member can bemade approximately equivalent to that of ceramic forming the tubularmember or the like. As a result, concentration of thermal stress at thebonding portion can be suppressed. Consequently, breakage of the bondingportion caused by thermal stress can be suppressed, and hence aworkpiece holder having high reliability can be obtained.

In the workpiece holder in accordance with the first or the secondaspect of the present invention may comprise another bond memberprovided, the portion for bonding the sealing member and the powersupply conductive member may have an additional bond member providedtherebetween. The additional bond member may have a surface extendingfrom a part of a surface of the sealing member onto a part of thesurface of the power supply conductive member, and the surface of thebond member preferably is a concave meniscus.

When the additional bond member forms a meniscus shape as describedabove, it is understood that the bond member has good wettability to thesurfaces of the sealing member and the power supply conductive member.That is, when the additional bond member has such a meniscus shape asdescribed above, the bonding portion between the sealing member and thepower supply conductive member has high airtightness. As a result, theoccurrence of leakage at the bonding portion can be effectivelyprevented.

In the holder in accordance with the first or the second aspect of thepresent invention, the additional bond member may include glass.

In this case, when glass for a bonding material is used for theadditional bond member, the heat treatment for forming the bond memberat the bonding portion between the sealing member and the power supplyconductive member can be performed at a relatively low temperature(approximately 1,000° C. or less). Accordingly, a greater freedom forselecting a material for forming the power supply conductive member canbe obtained.

In the workpiece holder in accordance with the first or the secondaspect of the present invention, the glass may be ZnO—SiO₂—B₂O₃-basedglass.

The ZnO—SiO₂—B₂O₃-based glass has a thermal expansion coefficientequivalent to that of ceramic, and such glass has good wettability tothe tubular member and the sealing member that are made of ceramic.Accordingly, when the ZnO—SiO₂—B₂O₃-based glass is used as the bondmember, airtightness and reliability of the bonding portion can beimproved.

In the workpiece holder in accordance with the first or the secondaspect of the present invention, the sealing member may include amaterial equivalent to that forming the tubular member.

In this case, the sealing member and the tubular member can be formed ofmaterials having thermal expansion coefficients equivalent to eachother. Accordingly, at the bonding portion between the sealing memberand the tubular member, concentration of thermal stress caused by thedifference in thermal expansion coefficient of the materials forming thesealing member and the tubular member can be suppressed. Hence, thereliability of the bonding portion described above can be improved.

In the workpiece holder in accordance with the first or the secondaspect of the present invention, the sealing member may include amaterial equivalent to that forming the ceramic body.

In this case, the sealing member and the ceramic body can be formed ofmaterials having thermal expansion coefficients equivalent to eachother. Accordingly, at the bonding portion between the sealing memberand the ceramic body, concentration of thermal stress caused by thedifference in thermal expansion coefficient of the materials forming thesealing member and the ceramic body can be suppressed. Hence, thereliability of the bonding portion described above can be improved.

In the workpiece holder in accordance with the first or the secondaspect of the present invention, the ceramic body may include aluminumnitride.

Aluminum nitride has high corrosion-resistance against halogenated gasesused for processing semiconductor substrates. In addition, the rate ofparticle generation of the ceramic body made of aluminum nitride issmaller than the rate of particle generation of that made of a materialother than aluminum nitride. Furthermore, since the thermal conductivityof aluminum nitride is relatively high, a temperature distribution on asurface (surface on which a workpiece such as a semiconductor substrateis mounted) of the ceramic body can be made uniform.

In the workpiece holder in accordance with the first or the secondaspect of the present invention, the power supply conductive member mayinclude an iron-nickel-cobalt alloy.

The difference in thermal expansion coefficient between theiron-nickel-cobalt alloy mentioned above and ceramic is relativelysmall. Accordingly, it is possible to decrease thermal stress generatedat the bonding portion between the power supply conductive member andthe sealing member when the bonding portion between the power supplyconductive member and the sealing member is formed and when theworkpiece holder is subjected to a heat cycle.

In addition, the iron-nickel-cobalt alloy described above has superiorwettability to glass used as the bond member. Accordingly, thereliability of the bonding portion between the power supply conductivemember and the sealing member can be improved.

In the workpiece holder in accordance with the first or the secondaspect of the present invention, the power supply conductive member mayinclude a base material and a coating layer. The base material maycontain at least one selected from the group consisting of tungsten,molybdenum, and an alloy thereof. The coating layer may be formed on asurface of the base material and may contain at least one of nickel andgold. In addition, the coating layer may be a plating layer containingat least one of nickel and gold.

In this case, the oxidation-resistance of a metal, such as tungsten,which forms the base material is not particularly superior; however, theoxidation-resistance of the power supply conductive member can beimproved by applying a coating layer containing nickel or gold thereon.In addition, the material forming the base material described above is ametal having a relatively low thermal expansion coefficient.Accordingly, when heat is applied to the bonding portion in the processof bonding the power supply conductive member and the sealing membertogether, for example, thermal stress generated thereby can bedecreased.

A processing apparatus in accordance with a third aspect of the presentinvention comprises the workpiece holder in accordance with the first orthe second aspect of the present invention.

By using a highly reliable workpiece holder made at a relativelyreasonable cost as described above, it is possible to manufacture ahighly reliable processing apparatus in which the treatment ofworkpieces such as substrates can be performed at a low cost.

Susceptors for use in semiconductor manufacturing apparatuses have beenrequired to be manufactured at a reasonable cost and also to be able towithstand severe conditions as in the case of etching treatment for asemiconductor substrate. The workpiece holder of the present inventioncan be fabricated, at a low cost, and can withstand severe operationconditions for use in a semiconductor manufacturing apparatus.

Embodiments

Hereinafter, embodiments of the present invention will be described withreference to figures. In the figures shown below, the same or theequivalent constituent element designates the same reference numeral,and the description thereof will not be repeated.

First Embodiment

FIG. 1 is a schematic cross-sectional view showing a workpiece holder,which is used in a processing apparatus, according to a first embodimentof the present invention. FIG. 2 is a schematic, enlarged,cross-sectional view showing a part of the workpiece holder shown inFIG. 1. FIG. 3 is a schematic, enlarged, cross-sectional view showing apart, which is different from that shown in FIG. 2, of the holder shownin FIG. 1. Referring FIGS. 1 to 3, the holder according to the firstembodiment of the present invention will be described.

As shown in FIGS. 1 to 3, a holder 1, which is a susceptor disposedinside a chamber of a processing apparatus, comprises a ceramic body 2,and a tubular member 6 bonded to this ceramic body 2 at the rear surfaceside thereof. The tubular member 6 is made of ceramic. The holder 1 isbonded to a wall surface (not shown) of the chamber at the bottomportion of the tubular member 6. As the processing apparatus, forexample, there may be mentioned a semiconductor manufacturing apparatus,such as an etching apparatus or a film-forming apparatus, used in stepsof manufacturing semiconductor substrates.

The ceramic body 2 holds on the surface thereof a workpiece such as asemiconductor substrate. The ceramic body 2 comprises a body base 3 madeof ceramic and electrical circuits including electrode 4 and a heatercircuit 5 embedded in this body base 3. The electrode 4 may be anelectrostatic chucking electrode for holding a workpiece such as asubstrate on the surface of the ceramic body 2 or may be aplasma-generating (radio frequency (RF)) electrode used for generatingplasma for processing the substrate. In addition, both electrostaticchucking electrode and plasma-generating electrode may be formed in theceramic body 2.

Power supply terminals 7 a to 7 c are connected to the electricalcircuits of the electrode 4 and the heater circuit 5. These power supplyterminals 7 a to 7 c are made of a conductive material such as a metaland are embedded in the ceramic body 2. One end of each of the powersupply terminals 7 a to 7 c is exposed at the surface of the ceramicbody 2 inside the tubular member 6. Terminal-side electrode lines 8 usedas power supply conductive members are disposed so as to be in contactwith these corresponding power supply terminals 7 a to 7 c. Theterminal-side electrode lines 8 are disposed inside the tubular member6. These terminal-side electrodes 8 are connected to correspondingpower-side electrode lines 9 at connection portions 10 with a gold (Au)brazing material 17. Nickel (Ni) may be used as a material for thepower-side electrode line 9. In addition to nickel (Ni), a conductivematerial having oxidation-resistance can be used as the material for thepower-side electrode line 9. A screw-in structure may be used as a jointstructure between the terminal-side electrode line 8 and the power-sideelectrode line 9. For example, a thread part may be formed at an endportion of the terminal-side electrode line 8, and a threaded hole inwhich the thread part is inserted and fixed may be formed at an endportion of the power-side electrode line 9, the end portion beingopposing the terminal-side electrode line 8. Subsequently, theterminal-side electrode line 8 and the corresponding power-sideelectrode line 9 may be connected and fixed together by inserting thethread part into the threaded hole and fixing together.

At the connection portions 10 between the terminal-side electrode lines8 and the power-side electrode lines 9, as shown in FIG. 2, end openingportions 15 are formed in the end portions of the power-side electrodelines 9. The end portions (end portions opposite to the ends connectedto the power supply terminals 7 a to 7 c) of the terminal-side electrodelines 8 are inserted into these corresponding end opening portions 15,and in the state described above, the Au brazing material 17 is filledinside the end opening portions 15.

In addition, inside the tubular member 6, a sealing member 11 made ofceramic is disposed in a region located above the connection portions 10between the terminal-side electrode lines 8 and the power-side electrodelines 9. The shape of the sealing member 11 in plan view isapproximately equivalent to the inside periphery of the tubular memberin the direction perpendicular to that in which the tubular member 6extends. In addition, a plurality of openings 12 is formed in thesealing member 11. The terminal-side electrode lines 8 are disposed soas to pass through these openings 12.

The terminal-side electrode lines 8 and the sealing member 11 are fixedtogether at the openings 12 with an additional bond member using glass13. The glass 13 serves as a sealing material for filling up theopenings 12, which are the bonding portions, such that a sealed region(a space in the first end portion side in the tubular member 6), whichis surrounded by the tubular member 6, the sealing member 11, and theceramic body 2 is isolated by the sealing member from other regions(opposite region, which is opposite to the sealed region in the tubularmember 6, and outer space surrounding the outer periphery of the holder1). In addition, the sealing member 11 and the tubular member 6 arebonded to and fixed to each other by the glass 13 functioning as a bondmember. As a result, the sealing chamber 11 can isolate the sealedregion inside the cylinder member 6 from the opposite region, which isopposite to the sealed region, inside the cylinder member. Furthermore,the terminal-side electrode lines 8 used as the power supply conductivemembers extend from the opposite region, penetrate the sealing member 11through the opening 12, to the sealed region inside the tubular member 6and are connected to the electrode 4 and the heater circuit 5 via thepower supply terminals 7 a to 7 c.

The glass 13 located at the bonding portion between the sealing member11 and the terminal-side electrode lines 8 and the glass 13 located atthe bonding portion between the sealing member 11 and the tubular member6 form meniscus portions 14. The meniscus portions 14 described aboveare formed when the wettability of the glass 13 to the surfaces of thesealing member 11, the terminal-side electrode line 8, and the tubularmember 6 is superior. When the meniscus portions 14 is formed asdescribed, the bonding portion exhibit high reliability, and leakage isunlikely to occur.

The glass 13 located at the bonding portion between the sealing member11 and the terminal-side electrode lines 8 and the glass 13 located atthe bonding portion between the sealing member 11 and the tubular member6 may be formed by performing heat treatment while a pressure of 100g/cm² or more is applied to the glass 13 through the sealing member 11.According to such treatment, the number of minute gaps can be reduced inthe glass 13. Hence, in addition to improvement in airtight property,the bonding strength of the bonding portion containing the glass 13 canbe improved.

A material having low oxidation-resistance, such as tungsten (W) ormolybdenum (Mo), is used as a material for forming the heater circuit 5or the electrodes 4. Similarly, the power supply terminals 7 a to 7 care made of a material having low oxidation-resistance in some cases. Inthe holder 1 of the present invention, the connection portions betweenthe terminal-side electrode lines 8 and power supply terminals of theheater circuit 5 or the like of the ceramic body 2 are located in thesealed region (region at the first end portion side of the tubularmember) surrounded by the sealing member 11, the tubular member 6, andthe ceramic body 2. Accordingly, if the bonding region between thetubular member 6 and the ceramic body 2, the bonding region between thetubular member 6 and the sealing member 11, and the bonding regionsbetween the sealing member 11 and the terminal-side electrode lines 8are formed so as to have predetermined airtightness, the region in whichthe connection portions between the terminal-side electrode lines 8 andthe power supply terminals 7 for the heater circuit 5 and the like arelocated becomes isolated from the atmosphere (other region) surroundingthe holder 1. Hence, when processing such as etching is performed, it ispossible to prevent occurrence of the problem that the connectionportions and the power supply terminals 7 for the heater circuit 5 andthe electrode 4 may be corroded by reacting gases present in theatmosphere around the holder 1.

In addition, since the sealing member 11 is disposed inside the tubularmember 6 so that the first region described above, that is, the regionin the tubular member 6 at the first end portion side, is isolated fromthe region other than the first region described above, plumbing forsupplying an inert gas into the tubular member 6, which has beenperformed in the past, is not necessary. Since the structure of theholder 1 can be simplified compared to that in the past, themanufacturing cost can be reduced. In addition, when a semiconductorsubstrate, that is, a workpiece, is processed (etching or the like)using the holder 1, it is not necessary to continuously supply an inertgas into the tubular member 6, and hence, the running cost can bereduced by using the holder 1.

Moreover the occurrence of a problem such as local concentration ofthermal stress caused by the change in an atmospheric temperature can besuppressed if suitable materials having thermal expansion coefficientswhich are not so different from each other are selected as materials forthe ceramic body 2, the tubular member 6, the sealing member 11, and theterminal-side electrode lines 8, which form the holder 1. Accordingly, aholder 1 having high reliability against thermal hysteresis due to heatcycle can be obtained.

In the holder 1 shown in FIGS. 1 to 3, since the sealing member 11 isdisposed at a distance from the surface of the ceramic body 2, thesealing member 11 is not in contact therewith. Consequently, it ispossible to prevent occurrence of the problem that the temperaturedistribution in the ceramic body 2 becomes uneven because of the sealingmember 11 being in contact with the ceramic body 2. As a result, theuniformity in temperature distribution in the ceramic body 2 can befurther improved.

Since the glass 13 used as the bond member is provided at the bondingportion between the tubular member 6 and the sealing member 11, gapsbetween the sealing member 11 and the tubular member 6 can be filledwith the glass 13. As a result, the airtight property of the bondingportion described above can be improved.

In addition, since the thermal expansion coefficient of the glass 13 isrelatively low than that of gold brazing material or the like, thethermal expansion coefficient of the glass 13 can be made approximatelyequivalent to that of ceramic forming the tubular member 6 if anappropriate type of glass 13 for the bond member is selected amongvarious materials. As a result, concentration of thermal stress at thebonding portion can be suppressed.

As shown in FIG. 3, the glass 13 has a surface extending from a part ofthe surface of the tubular member 6 to a part of the surface of thesealing member 11, and the glass has a concave cross-sectional shape (aso-called meniscus portion 14 is formed). The meniscus portion 14described above is formed when the glass 13 has good wettability to thesurfaces of the tubular member 6 and the sealing member 11. That is,when the bond member has the concave meniscus, the bonding portion hashigh airtightness.

In addition, in the holder 1 shown in FIGS. 1 to 3, the glass 13 isprovided as an additional bond member at the bonding portions betweenthe sealing member 11 and the terminal-side electrode lines 8. As shownin FIG. 2, the glass 13 has a surface extending from a part of thesurface of the sealing member 11 onto a part of the surface of theterminal-side electrode line 8, and the surface of the glass 13 is aconcave meniscus (a meniscus portion 14 is formed). When the meniscusportion 14 described above is formed on the surface of the glass 13, itis understood that the glass 13 has good wettability to the surfaces ofthe sealing member 11 and the terminal-side electrode lines 8. That is,when the meniscus portion 14 described above is formed, the bondingportions between the sealing member 11 and the terminal-side electrodelines 8 have a high airtight property. In addition, when the glass 13 isused as said another bond member, a heat treatment step of providing theglass 13 at the bonding portions between the sealing member 11 and theterminal-side electrode lines 8 can be performed at a relatively lowtemperature (approximately 1,000° C. or less). As a result, the degreeof freedom for selecting a material forming the terminal-side electrodelines 8 can be made larger.

As the glass 13, ZnO—SiO₂—B₂O₃-based glass may be used.ZnO—SiO₂—B₂O₃-based glass has a thermal expansion coefficient equivalentto that of ceramic and superior wettability to the tubular member 6 andthe sealing member 11 that are made of ceramic. Therefore, if suchZnO—SiO₂—B₂O₃-based glass is used as the glass 13, the airtightness andreliability of the bonding portion can be improved.

In addition, a material forming the sealing member 11 may contain thesame material as that forming the tubular member 6. When the material isthus selected, the sealing member 11 can be formed of a material havinga thermal expansion coefficient approximately equivalent to that of thetubular member 6. Accordingly, it is possible to prevent the thermalstress from being concentrated at the bonding portion between thesealing member 11 and the tubular member 6 because of the difference inthermal expansion coefficient between the materials of the sealingmember 11 and the tubular member 6.

A material forming the sealing member 11 may contain the same materialas that for the body base 3 forming the ceramic body 2.

In the case described above, the sealing member 11 and the ceramic body2 can be formed of materials having thermal expansion coefficientsapproximately equivalent to each other. Accordingly, when the sealingmember 11 and the ceramic body 2 are directly bonded together as in thecase of the holder 1 described later in a third embodiment of thepresent invention, it is possible to prevent the thermal stress frombeing concentrated at the bonding portion because of the difference inthermal expansion coefficient between the materials of the sealingmember 11 and the ceramic body 2.

A material for the body base 3 forming the ceramic body 2 may containaluminum nitride. Aluminum nitride has high corrosion resistance againsthalogenated gases used for processing a semiconductor substrate. Inaddition, the ceramic body 2 containing aluminum nitride exhibits alower rate of generation of particles compared with a ceramic bodycontaining other material. Furthermore, since the thermal conductivityof aluminum nitride is relatively high, a temperature distribution on asurface (surface on which a workpiece such as a semiconductor substrateis mounted) of the ceramic body 2 can be made uniform.

In addition, the region surrounded by the sealing member 11, the tubularmember 6, and the ceramic body 2 is preferably in an evacuated or anon-oxidizing state. In this case, oxidation can be effectivelysuppressed from occurring at the terminal-side electrode lines 8, or theconnection portions between the terminal-side electrode lines 8 and thepower supply terminals for the heater circuit 5 or the electrode 4,which are located in the region described above.

An ion-nickel-cobalt alloy may be used as a material for forming theterminal-side electrode lines 8. In this case, the thermal expansioncoefficient of an ion-nickel-cobalt alloy is not so different from thatof ceramic. Accordingly, the thermal stress generated at the bondingportion between the terminal-side electrode line 8 and the sealingmember 11 can be suppressed when the bonding portion between theterminal-side electrode line 8 and the sealing member 11 made of ceramicis formed, and when the holder 1 is subjected to heat cycle. Inaddition, the ion-nickel-cobalt alloy described above has superiorwettability to glass used as the bond member. Hence, the reliability ofthe bonding portion between the terminal-side electrode line 8 and thesealing member 11 can be improved.

The terminal-side electrode line 8 used as the power supply conductivemember may comprise a base material containing at least one selectedfrom the group consisting of tungsten (W), molybdenum (Mo), and an alloythereof and a plating layer which is formed on the base material andwhich serves as a coating layer containing at least one of nickel andgold. In this case, the difference in thermal expansion coefficientbetween ceramic and the above-mentioned metal forming the base materialis relatively small. Accordingly, when the bonding portion between theterminal-side electrode line 8 and the sealing member 11 is formed,concentration of thermal stress generated at the bonding portion, whichis caused by the difference in thermal expansion coefficient between theterminal-side electrode line 8 and the sealing member 11, can besuppressed.

The rate of helium leak from the sealed region surrounded by the sealingmember 11, the tubular member 6, and the ceramic body 2 to other regionis preferably 10⁻⁸ Pa·m³/s or less. In this case, oxidation of theterminal-side electrode lines 8 and the connection portions between theterminal-side electrode 8 and the power supply terminals for the heatercircuit 5 and the electrode 4, which are located in the sealed region,can be securely suppressed.

When the holder 1 shown in FIGS. 1 to 3 is applied to a processingapparatus for processing a semiconductor substrate, a semiconductorsubstrate can be processed at an inexpensive cost, and in addition tothat, a processing apparatus having high reliability can be realized.

Second Embodiment

FIG. 4 is a schematic, cross-sectional view of a holder according to asecond embodiment of the present invention. With reference to FIG. 4,the holder according to the second embodiment of the present inventionwill be described.

As shown in FIG. 4, the holder 1 of this embodiment has the structurebasically equivalent to that shown in FIGS. 1 to 3; however, aprotruding portion 18 for defining the position of the sealing member 11is formed on the inside wall of the tubular member 6. While an endportion of the sealing member 11 is pressed against this protrudingportion 18, the tubular member 6 and the sealing member 11 are bondedand fixed together with the glass 13 provided therebetween.

According to the structure described above, the same advantage as thatof the holder 1 shown in FIGS. 1 to 3 can be obtained, and at the sametime, by the presence of the protruding portion 18, an area at which thetubular member 6 and the sealing member 11 oppose each other can beincreased. Accordingly, the reliability of the bonding portion betweenthe tubular member 6 and the sealing member 11 can be increased. As aresult, the rate of leak generation can be effectively decreased.

Third Embodiment

FIG. 5 is a schematic, cross-sectional view of a holder according to athird embodiment of the present invention. With reference to FIG. 5, theholder according to the third embodiment of the present invention willbe described.

As shown in FIG. 5, the holder 1 of this embodiment has the structurebasically equivalent to that shown in FIGS. 1 to 3; however, theposition at which the sealing member 11 is disposed is different. Thatis, the sealing member 11 is disposed inside the tubular member 6 so asto be in close contact with the rear surface of the ceramic body 2.

In addition, the sealing member 11 thus disposed is fixed to the tubularmember 6 and the terminal-side electrode lines 8 with the glass 13.

According to the structure described above, the same advantage as thatof the holder 1 shown in FIGS. 1 to 3 can be obtained, and at the sametime, since the sealing member 11 is in contact with the rear surface ofthe ceramic body 2, the ceramic body 2 can hold the sealing member 11.As a result, the thickness of the sealing member 11 can be decreased.Hence, the degree of freedom for designing the sealing member 11 can bemade larger.

In addition, in the case described above, by providing glass whichfunctions as a fixing bond member between the ceramic body 2 and thesealing member 11, the ceramic body 2 and the sealing member 11 may bebonded to each other. Accordingly, the same advantage as that of theholder 1 shown in FIG. 4 can be obtained. In addition, the glassprovided between the ceramic body 2 and the sealing member 11 may beformed by heat treatment while being pressed at a pressure of 100 g/cm²or more through the sealing member 11 side. In this case, since thenumber of minute gaps can be removed by the glass, airtightness of thebonding portion between the ceramic body 2 and the sealing member 11 canbe improved, and in addition to this, the bonding strength can beimproved.

Fourth Embodiment

FIG. 6 is a schematic, cross-sectional view of a holder according to afourth embodiment of the present invention. FIG. 7 is a schematic,cross-sectional view showing a part of the holder shown in FIG. 6. Withreference to FIGS. 6 and 7, the holder according to the fourthembodiment of the present invention will be described.

As shown in FIGS. 6 and 7, the holder 1 used as a susceptor for asemiconductor manufacturing apparatus has the structure basicallyequivalent to that shown in FIG. 5; however, the structure of a sealingmember 21 (see FIG. 6) is different therefrom. That is, in the holder 1shown in FIGS. 6 and 7, tubular sealing members 21 are disposed insidethe tubular member 6 so as to surround the peripheries of the connectionportions between the terminal-side electrode lines 8 used as the powersupply conductive members and the electrical circuits such as theelectrode 4 and the heater circuit 5. The sealing members 21 are bondedto and fixed to the surface of the ceramic body 2, which containsaluminum nitride, with the glass 13. In addition, inside the sealingmember 21 (an opening portion in the sealing member 21), theterminal-side electrode line 8 is disposed, and between theterminal-side electrode line 8 and the sealing member 21, the glass 13is provided as said another bond member. As a material for theterminal-side electrode line 8, an iron-nickel-cobalt alloy may be used.The sealing member 21 isolates the connection portions of theterminal-side electrode lines 8 with the heater circuit 5 and theelectrode 4 from the atmosphere surrounding the periphery of the sealingmember 21.

The glass 13 functioning as said another bond member has a surfaceextending from a part of the surface of the sealing member 21 to a partof the surface of the terminal-side electrode line 8, and the glass 13has a concave cross-sectional shape (so-called meniscus is formed). As aresult, as in the case of the holder 1 in the first embodiment of thepresent invention, a high airtightness can be obtained by means of theglass 13 at the bonding portion between the sealing member 21 and theterminal-side electrode line 8.

In addition, in the holder 1 shown in FIGS. 6 and 7, the connectionportions between the terminal-side electrode -lines 8 and the electricalcircuits of the ceramic body 2, such as the power supply terminals forthe heater circuit 5 and the electrode 4, are located in the regionssurrounded by the sealing members 21 and the ceramic body 2. When thebonding regions between the sealing members 21 and the ceramic body 2are formed with the glass 13 so as to have a predetermined airtightness,and the sealing members 21 and the terminal-side electrode lines 8 arefixed together with the glass 13, the regions in which the connectionportions are located are isolated from an atmosphere (other region)surrounding the peripheries of the sealing members 21. Accordingly, asin the first embodiment of the present invention, it is possible toprevent an occurrence of the problem that the electrical circuits ormaterials forming the connection portions are corroded by oxygen in theair present inside the tubular member 6 or the like when heat treatmentsuch as etching is performed.

In addition, since the sealing members 21 are disposed inside thetubular member 6, and the connection portions described above areisolated (sealed) from the region surrounding the peripheries of thesealing members 21, plumbing for supplying an inert gas into the tubularmember 6, which has been performed in the past, is not necessary.Accordingly, since the structure of the holder 1 can be simplified, themanufacturing cost can be reduced. In addition, when a workpiece isprocessed by etching or the like using the holder 1, it is not necessaryto continuously supply an inert gas into the tubular member 6, andhence, the running cost can be reduced by using the holder 1.

Materials having thermal expansion coefficients not largely differentfrom each other may be used as materials for the ceramic body 2, thesealing member 21, the terminal-side electrode line 8, and thepower-side electrode line 9. In this case, thermal stress can beprevented being locally concentrated at, for example, the bondingportion between the materials for the sealing member 21 and the ceramicbody 2 due to the change in ambient temperature.

As described above, since the sealing members 21 are each provided foreach of the connection portions between the terminal-side electrodelines 8 and the electrical circuits such as the heater circuit 5 and theelectrode 4, the size of the sealing member 21 can be decreased.Accordingly, the cost of the sealing member 21 can be reduced. Inaddition, since an area at which the ceramic body 2 and the sealingmembers 21 are in contact with each other can be decreased, influence ofthe sealing member 21 on a temperature distribution in the ceramic body2 can be reduced. As a result, since the temperature distribution in theceramic body 2 can be made more uniform, a temperature distribution of aworkpiece such as a semiconductor substrate placed on the ceramic body 2can also be made uniform.

In the holder 1 shown in FIGS. 6 and 7, the glass 13 is filled as anadditional bond member between the terminal-side electrode lines 8 andthe sealing members 21 at the connection portions between theterminal-side electrode lines 8 and the power supply terminals for theheater circuit 5 and the electrode 4. In the case, as long as thesealing member 21 and the terminal-side electrode line 8 are securelybonded together and sealed at the bottom of the sealing member 21, a gapmay be formed between the inside wall of the sealing member 21 and theterminal-side electrode line 8 at, for example, the central or the upperportion of the sealing member 21. Preferably, the gap should be vacuumor non-oxidizing atmosphere. In this case, the terminal-side electrodelines 8 and the connection portions between the terminal-side electrodelines 8 and the electrical circuits such as the heater circuit 5 can beeffectively prevented from being oxidized.

In the holder 1, the rate of helium leak to a region surrounding thesealing member 21 from the region in which the connection portionbetween the terminal-side electrode line 8 and the electrical circuitsuch as the heater circuit 5 is located is preferably 10⁻⁸Pa·m³/s orless. In this case, oxidation of the terminal-side electrode lines 8 andthe connection portions between the terminal-side electrode lines 8 andthe power supply terminals for the heater circuit 5 and the like, whichare located inside the sealing member 21, can be securely suppressed.

In the holder 1, at the bonding portion between the ceramic body 2 andthe sealing member 21, the glass functioning as a bond member may beprovided therebetween. In this case, the gaps between the sealing member21 and the ceramic body 2 can be filled with the glass. As a result, theairtight property of the bonding portion can be improved.

As shown in FIGS. 6 and 7, the glass 13 functioning as the bond memberhas a surface extending from a part of the rear surface of the ceramicbody 2 onto a part of the surface of the sealing member 21, and thesurface of the glass 13 is a concave meniscus. In this case, it isunderstood that the glass 13 has good wettability to the surfaces of thesealing member 21 and the ceramic body 2 and the ceramic body 2 and thatthe bonding portion between the sealing member 21 and the ceramic body 2has high airtightness. As a result, leak generation at the bondingportion can be prevented without fail.

ZnO—SiO₂—B₂O₃-based glass may be used as the glass 13, as in the firstembodiment of the present invention. In addition, a material for formingthe sealing member 21 may contain a material equivalent to that formingthe tubular member 6. Furthermore, a material for forming the sealingmember 21 may contain a material forming the ceramic body 2.

FIG. 8 is a schematic, cross-sectional view showing a first modifiedexample of the holder 1 shown in FIGS. 6 and 7 according to the fourthembodiment of the present invention. FIG. 9 is a schematic,cross-sectional view showing a part of the workpiece holder shown inFIG. 8. With reference to FIGS. 8 and 9, the first modified example ofthe holder according to the fourth embodiment of the present inventionwill be described.

As shown in FIGS. 8 and 9, the holder 1 used as a susceptor for asemiconductor manufacturing apparatus has the structure basicallyequivalent to that of the holder 1 shown in FIGS. 6 and 7 except thatthe shape of the glass 13 for bonding the sealing member 21 to theceramic body 2 is different. That is, in the holder 1 shown in FIGS. 8and 9, the glass 13 is provided between the sealing member 21 and theceramic body 2. In addition, the glass 13 is disposed so as to surroundand seal the connection portions between the terminal-side electrodelines 8 and the power supply terminals 7 a to 7 c. Furthermore, betweenthe sealing member 21 and the terminal-side electrode line 8, there is aspace in which the glass 13 is not provided. That is, between thesealing member 21 and the terminal-side electrode line 8, the glass 13is only provided at the ceramic body 2 side. This structure can providethe same advantage as that of the holder 1 shown in FIGS. 6 and 7.

In heat treatment for fixing the glass 13 in the holder 1, a pressure ispreferably applied to the glass 131 through the sealing member 21. Inthis case, a pressure of 100 g/cm² or more is preferably applied to theglass 13 from the sealing member 21 side. Accordingly, the number ofminute gaps present at the interface between the glass 13 and theceramic body 2, the sealing member 21, or the terminal-side electrodeline 8 can be reduced or can be removed. As a result, the rate of heliumleak from each of the regions in which the connection portions betweenthe power supply terminals 7 a to 7 c and the terminal-side electrodelines 8 are located can be reduced, that is, the airtightness can beimproved. In addition, when a pressure of 100 g/cm² or more is applied,the advantage approximately equivalent to that in the fourth embodimentcan be obtained; however, when the pressure is less than 100 g/cm², asignificant effect of decreasing the helium leak rate cannot beobtained.

FIG. 10 is a schematic, cross-sectional view showing a second modifiedexample of the holder 1 shown in FIGS. 6 and 7 according to the fourthembodiment of the present invention. FIG. 11 is a schematic,cross-sectional view showing a part of the workpiece holder shown inFIG. 10. With reference to FIGS. 10 and 11, the second modified exampleof the holder according to the fourth embodiment of the presentinvention will be described.

As shown in FIGS. 10 and 11, the holder 1 used as a susceptor for asemiconductor manufacturing apparatus has the structure basicallyequivalent to that of the holder 1 shown in FIGS. 8 and 9 except thatthe shape of the surface of the ceramic body 2 is different. That is, inthe holder 1 shown in FIG. 10, three grooves 25 (see FIG. 11) are formedin the rear surface side of the ceramic body 2. The shape of the groove25 in plan view may be a circular or polygonal shape. In addition, atthe bottom walls of the grooves 25, the power supply terminals 7 a to 7c are exposed. The end surfaces of the power supply terminals 7 a to 7 cexposed at the bottom walls of the grooves 25 are connected to thecorresponding terminal-side electrode lines 8. The sealing members 21and the glass 13 are provided around the connection portions between thepower supply terminals 7 a to 7 c and the terminal-side electrode lines8, as is the holder 1 shown in FIGS. 8 and 9.

The structure thus formed provides the advantage equivalent to that ofthe holder 1 shown in FIGS. 8 and 9. In addition, since the connectionportions between the power supply terminals 7 a to 7 c and theterminal-side electrode lines 8 are disposed inside the grooves 25, ifany stress is applied to the terminal-side electrode lines 8 in thelateral direction (that is, when stress in the lateral direction isapplied to the connection portions, for example), the stress isdispersedly applied not only to the bonding portions between the glass13 and the bottom walls of the grooves 25 but also to the sidewalls ofthe grooves 25. Accordingly, the durability of the connection portionscan be improved. In this case, the glass 13 or the sealing member 21 ispreferably disposed so as to be in contact with the sidewalls of thegroove 25. With such structure, since the glass 13 or the sealing member21 is supported by the sidewalls of the groove 25, the durability of theconnection portion against an external force can be effectivelyimproved.

In the embodiments described above of the present invention, theconnection portions between the power supply terminals 7 a to 7 c andthe terminal-side electrode lines 8 may have a screw-in structure. Forexample, a thread part may be formed at an end portion of each of thepower supply terminals 7 a to 7 c, and a threaded hole may be formed atthe upper portion (opposing each of the power supply terminals 7 a to 7c) of each of the terminal-side electrode lines 8. Subsequently, byinserting the thread part into the threaded hole and fixing together,the terminal-side electrode lines 8 and the corresponding power supplyterminals 7 a to 7 c may be connected to each other.

EXAMPLES

In order to prove the advantage of the holder according to the presentinvention, the following experiments were carried out.

First, four types of powdered starting materials having the compositionsshown in Table I were prepared. TABLE I No. Mass ratio Composition 1AlN:Y₂O₃ = 100:5 Composition 2 AlN:Y₂O₃ = 100:0.5 Composition 3Al₂O₃:CaO:MgO = 100:0.2:0.2 Composition 4 AlN:CaO = 100:2.0

To each of the starting materials having the compositions shown in theabove Table I, a binder and a solvent were added, and subsequently,mixing was performed using a ball mill, so that slurries havingcompositions (compositions 1 to 4) were formed.

Next, the individual slurries having compositions 1 to 4 shown in TableI were formed into sheets by a doctor blade method. The sheets (greensheets) thus formed were cut into a circular shape so as to have adiameter of 350 mm after sintering was performed. Subsequently, a pastecontaining tungsten (W) was applied to the circular sheets thus formedby a screen printing method, thereby forming a heater circuit.

Next, a plurality of sheets, which were not provided with heatercircuits, was laminated on the surface on which the heater circuitdescribed above was formed. In addition, on the surface of thislaminate, a sheet having a plasma-forming IF) electrode or anelectrostatic electrode (electrostatic chucking), which was formed byapplying a paste containing tungsten by a screen printing method, waslaminated. Thus, a laminate made of the sheets was formed.

The laminate sheets thus formed were degreased by heat treatment at aheating temperature of 700° C. in a nitrogen atmosphere.

Next, the laminates using slurries having compositions 1, 2, and 4 weresintered at a heating temperature of 1,800° C. in a nitrogen atmosphere.The laminate made of a slurry having composition 3 was sintered at aheating temperature of 1,600° C. in a nitrogen atmosphere. Subsequently,power supply terminals for supplying current to the heater circuit andthe electrostatic electrode or the plasma-forming electrode were formedat predetermined positions. Thus, ceramic bodies composed of thecompositions described above were formed.

Next, each of the slurries having compositions 1 to 4 shown in Table Iwas formed into pellets by a spray dry method. By using the pellets asstarting material, cylindrical molded bodies were formed by a dry pressmethod. These molded bodies were degreased at a heating temperature of700° C. in a nitrogen stream. Subsequently, sintering treatment wasperformed under the same conditions as those for the above-describedsintering of the ceramic bodies having the compositions 1 to 4,respectively.

After the above sintering treatment was performed, machining wasperformed for the cylindrical sintered bodies thus formed. As a result,tubular members 50 mm in inside diameter, 60 mm in outside diameter, and200 mm long were obtained.

In addition to those tubular members, tubular members having a structuredifferent from that of the tubular members described above were formedby steps equivalent to those described above. On the inside wall ofthese tubular members, a protruding portion for holding the sealingmember was provided at a distance of 30 mm from the bonding portion (endof the tubular member) to be bonded with a ceramic body. The protrudingportion functioning as a holding part was 5 mm high (height from theinside wall of the tubular member) and 40 mm in inside diameter.

Slurry made of Al₂O₃—Y₂O₃—AlN was applied to an end surface of thetubular member. The tubular members and the ceramic bodies were joinedtogether with the slurry coated surface in contact with the rear surfaceof the ceramic bodies, and the joint bodies thus formed were subjectedto heat treatment under the same conditions as those of the process forsintering the ceramic bodies. As a result, each ceramic body and eachtubular member were bonded together. In each joint body, the end of therespective power supply terminals for supplying electrical power fromthe outside to a heater circuit, the electrostatic electrode, and theplasma-forming electrode, which were embedded inside the ceramic body,was exposed at a surface area that was located inside the tubularmember.

Next, the terminal-side electrode lines used as power supply memberswere connected to the power supply terminals for the heater circuit, theelectrostatic electrode, and the plasma-forming electrode. Through theseelectrode lines, current could be supplied to the heater circuit, theelectrostatic electrode, and the plasma-forming electrode.

In addition, the sheets having the compositions 1 to 4 respectively werecut into a predetermined size, and subsequently, they were subjected toheat treatment to become a sintered bodies as in the case of forming theceramic bodies. The sintered bodies may be formed by laminating aplurality of sheets, if necessary, to have a predetermined thickness.Next, the sintered body thus formed were subjected to machining so as toform opening portions therein for the terminal-side electrode lines topenetrate. In addition, the laminated bodies were subjected to machiningto adjust their peripheral dimensions so that they could be insertedinside the tubular member. Thus, the sealing members were formed. Inaddition, another type of sealing members, which were used for eachconnection portion between the terminal-side electrode line and theelectrical circuit as described in the fourth embodiment of the presentinvention, were formed in a similar manner.

Subsequently, after each ceramic body was provided with the tubularmember, the power supply terminals, and the electrode lines functioningas the power supply members, the sealing members were each insertedinside the tubular member. Alternatively, a joint body may be formed byfixing the sealing member to the inside of the tubular member, and thenthe joint body may be bonded to the ceramic body. In addition, theabove-mentioned another type of sealing members was provided on theceramic body so as to surround each connection portion of theterminal-side electrode line.

Subsequently, glass was applied between the tubular member and thesealing member, and between the electrode line and the sealing member,respectively. The sealing members were respectively fixed by firingtreatment at a temperature of 700° C. in a nitrogen atmosphere, in anargon atmosphere, in an evacuated atmosphere, or in the air such thatthe region surrounded by the sealing member, the tubular member, and theceramic body was sealed. In addition, on the sample having theabove-mentioned another type of sealing members, glass was appliedbetween the sealing members and the ceramic body and between theelectrode line and the sealing member, respectively, and thereafter heattreatment (firing treatment) was performed in a manner similar to thatdescribed above. In some samples, the heat treatment was performed whilea pressure of 100 g/cm² or more was applied to the glass through thesealing member. Thus, the sealing members were respectively fixed, andeach region surrounded by the sealing member and the ceramic body wassealed. The glass used for sealing in these examples was ZnO—SiO₂—B₂O₃crystallized glass.

According to the methods described above, 68 samples shown in Tables IIto VI were prepared. In addition, in order to prove the influence ofpressure applied during firing treatment of the glass, 39 samples(sample Nos. 69 to 107) shown in Tables VII to IX were prepared. TablesII to IX show the conditions for fabricating the samples used in thefollowing tests and the evaluation results thereof. TABLE II MaterialOxidation Sam- Material for Material for for Formation resistance pleMaterial for tubular sealing Sealing electrode of Leak rate (750° C. inNo. Type ceramic body member member Sealing atmosphere line meniscus (Pa· m³/s) the air) 1 Example Composition 1 Composition 1 Composition 1Space N₂ Kovar Yes 10⁻⁸ or less Good 2 Example Composition 1 Composition1 Composition 1 Space Ar Kovar Yes 10⁻⁸ or less Good 3 ExampleComposition 1 Composition 1 Composition 1 Space Vacuum Kovar Yes 10⁻⁸ orless Good 4 Comparative Composition 1 Composition 1 Composition 1 SpaceAir Kovar No Not sealable example (Oxidation of power supply terminal) 5Comparative Composition 1 Composition 1 Composition 3 Space N₂ Kovar NoNot sealable example (Oxidation of power supply terminal) 6 ComparativeComposition 1 Composition 1 Composition 1 Space N₂ Ni No Not sealableexample (Glass breakage) 7 Example Composition 1 Composition 1Composition 2 Space N₂ Kovar Yes 10⁻⁸ or less Good 8 Example Composition1 Composition 1 Composition 4 Space N₂ Kovar Yes 10⁻⁸ or less Good 9Example Composition 2 Composition 2 Composition 1 Space N₂ Kovar Yes10⁻⁸ or less Good 10 Example Composition 3 Composition 3 Composition 3Space N₂ Kovar Yes 10⁻⁸ or less Good 11 Comparative Composition 3Composition 3 Composition 1 Space N₂ Kovar No Not sealable example(Glass breakage) 12 Example Composition 1 Composition 2 Composition 4Space N₂ Kovar Yes 10⁻⁸ or less Good 13 Example Composition 1Composition 1 Composition 1 Contact N₂ Kovar Yes 10⁻⁸ or less Good 14Example Composition 1 Composition 1 Composition 1 Contact Ar Kovar Yes10⁻⁸ or less Good 15 Example Composition 1 Composition 1 Composition 1Contact Vacuum Kovar Yes 10⁻⁸ or less Good

TABLE III Material Oxidation Material for Material for Material for forFormation resistance Sample ceramic tubular sealing Sealing electrode ofLeak rate (750° C. in No. Type body member member Sealing atmosphereline meniscus (Pa · m³/s) the air) 16 Comparative Composition 1Composition 1 Composition 1 Contact Air Kovar No Not example sealable(Oxidation of power supply terminal) 17 Comparative Composition 1Composition 1 Composition 3 Contact N₂ Kovar No Not example sealable(Oxidation of power supply terminal) 18 Comparative Composition 1Composition 1 Composition 1 Contact N₂ Ni No Not example sealable (Glassbreakage) 19 Example Composition 1 Composition 1 Composition 2 ContactN₂ Kovar Yes 10⁻⁸ or less Good 20 Example Composition 1 Composition 1Composition 4 Contact N₂ Kovar Yes 10⁻⁸ or less Good 21 ExampleComposition 2 Composition 2 Composition 1 Contact N₂ Ni Yes 10⁻⁸ or lessGood 22 Example Composition 3 Composition 3 Composition 3 Contact N₂Kovar Yes 10⁻⁸ or less Good 23 Comparative Composition 3 Composition 3Composition 1 Contact N₂ Kovar No NOT example sealable (Glass breakage)24 Example Composition 1 Composition 2 Composition 4 Contact N₂ KovarYes 10⁻⁸ or less Good

TABLE IV Material Oxidation Sam- Material for Material for for Formationresistance ple Material for tubular sealing Sealing electrode of Leakrate (750° C. in No. Type ceramic body member member Sealing atmosphereline meniscus (Pa · m³/s) the air) 25 Example Composition 1 Composition1 Composition 1 Individual N₂ Kovar Yes 10⁻⁸ or less Good 26 ExampleComposition 1 Composition 1 Composition 1 Individual Ar Kovar Yes 10⁻⁸or less Good 27 Example Composition 1 Composition 1 Composition 1Individual Vacuum Kovar Yes 10⁻⁸ or less Good 28 Comparative Composition1 Composition 1 Composition 1 Individual Air Kovar No Not sealableexample 29 Example Composition 1 Composition 1 Composition 3 IndividualN₂ Kovar Yes 10⁻⁸ or less Good 30 Comparative Composition 1 Composition1 Composition 1 Individual N₂ Ni No Not sealable example 31 ExampleComposition 1 Composition 1 Composition 2 Individual N₂ Kovar Yes 10⁻⁸or less Good 32 Example Composition 1 Composition 1 Composition 4Individual N₂ Kovar Yes 10⁻⁸ or less Good 33 Example Composition 2Composition 2 Composition 1 Individual N₂ Kovar Yes 10⁻⁸ or less Good 34Example Composition 3 Composition 3 Composition 3 Individual N₂ KovarYes 10⁻⁸ or less Good 35 Comparative Composition 3 Composition 3Composition 1 Individual N₂ Kovar No Not sealable example 36 ExampleComposition 1 Composition 2 Composition 4 Individual N₂ Kovar Yes 10⁻⁸or less Good

TABLE V Material Oxidation Material for Material for for Formationresistance Sample Material for tubular sealing Sealing electrode of Leakrate (750° C. in No. Type ceramic body member member Sealing atmosphereline meniscus (Pa · m³/s) the air) 37 Comparative Composition 1Composition 1 Composition 1 Space N₂ W (No Yes 10⁻⁸ or less Oxidizedexample plating) 38 Example Composition 1 Composition 1 Composition 1Space N₂ W-1 Yes 10⁻⁸ or less Good 39 Example Composition 1 Composition1 Composition 1 Space Vacuum W-2 Yes 10⁻⁸ or less Good 40 ExampleComposition 1 Composition 1 Composition 1 Space N₂ W-3 Yes 10⁻⁸ or lessGood 41 Comparative Composition 1 Composition 1 Composition 1 Space N₂Cu—W Yes 10⁻⁸ or less Oxidized example (No plating) 42 ExampleComposition 1 Composition 1 Composition 1 Space N₂ Cu—W-1 Yes 10⁻⁸ orless Good 43 Example Composition 1 Composition 1 Composition 1 Space N₂Cu—W-2 Yes 10⁻⁸ or less Good 44 Example Composition 1 Composition 1Composition 1 Space N₂ Cu—W-3 Yes 10⁻⁸ or less Good 45 ComparativeComposition 1 Composition 1 Composition 1 Space N₂ Mo (No Yes 10⁻⁸ orless Oxidized example plating) 46 Example Composition 1 Composition 1Composition 1 Space N₂ Mo-1 Yes 10⁻⁸ or less Good 47 Example Composition1 Composition 1 Composition 1 Space N₂ Mo-2 Yes 10⁻⁸ or less Good 48Example Composition 1 Composition 1 Composition 1 Space N₂ Mo-3 Yes 10⁻⁸or less Good 49 Comparative Composition 1 Composition 1 Composition 1Space N₂ Cu—Mo Yes 10⁻⁸ or less Oxidized example (No plating) 50 ExampleComposition 1 Composition 1 Composition 1 Space N₂ Cu—Mo-1 Yes 10⁻⁸ orless Good 51 Example Composition 1 Composition 1 Composition 1 Space N₂Cu—Mo-2 Yes 10⁻⁸ or less Good 52 Example Composition 1 Composition 1Composition 1 Space N₂ Cu—Mo-3 Yes 10⁻⁸ or less Good

TABLE VI Oxidation Material for Material for Material for Material forFormation Leak resistance Sample ceramic tubular sealing Sealingelectrode of rate (750° C. in No. Type body member member Sealingatmosphere line meniscus (Pa · m³/s) the air) 53 Comparative Composition1 Composition 1 Composition 1 Contact N₂ W (No Yes 10⁻⁸ or Oxidizedexample plating) less 54 Example Composition 1 Composition 1 Composition1 Contact N₂ W-1 Yes 10⁻⁸ or Good less 55 Example Composition 1Composition 1 Composition 1 Contact Vacuum W-2 Yes 10⁻⁸ or Good less 56Example Composition 1 Composition 1 Composition 1 Contact N₂ W-3 Yes10⁻⁸ or Good less 57 Comparative Composition 1 Composition 1 Composition1 Space N₂ Cu—W Yes 10⁻⁸ or Oxidized example (No less plating) 58Example Composition 1 Composition 1 Composition 1 Space N₂ Cu—W-1 Yes10⁻⁸ or Good less 59 Example Composition 1 Composition 1 Composition 1Space N₂ Cu—W-2 Yes 10⁻⁸ or Good less 60 Example Composition 1Composition 1 Composition 1 Space N₂ Cu—W-3 Yes 10⁻⁸ or Good less 61Comparative Composition 1 Composition 1 Composition 1 Space N₂ Mo (NoYes 10⁻⁸ or Oxidized example plating) less 62 Example Composition 1Composition 1 Composition 1 Space N₂ Mo-1 Yes 10⁻⁸ or Good less 63Example Composition 1 Composition 1 Composition 1 Space N₂ Mo-2 Yes 10⁻⁸or Good less 64 Example Composition 1 Composition 1 Composition 1 SpaceN₂ Mo-3 Yes 10⁻⁸ or Good less 65 Comparative Composition 1 Composition 1Composition 1 Space N₂ Cu—Mo Yes 10⁻⁸ or Oxidized example (No lessplating) 66 Example Composition 1 Composition 1 Composition 1 Space N₂Cu—Mo-1 Yes 10⁻⁸ or Good less 67 Example Composition 1 Composition 1Composition 1 Space N₂ Cu—Mo-2 Yes 10⁻⁸ or Good less 68 ExampleComposition 1 Composition 1 Composition 1 Space N₂ Cu—Mo-3 Yes 10⁻⁸ orGood less

TABLE VII Material Oxidation Material for Material for Material for forLoad resistance Sample ceramic tubular sealing Sealing electrode forLeak rate (750° C. in No. Type body member member Sealing atmosphereline sealing (Pa · m³/s) the air) 69 Example Composition 1 Composition 1Composition 1 Contact N₂ Kovar No 10⁻⁸ or less Good with glass (FIG. 8)70 Comparative Composition 1 Composition 1 Composition 1 Contact N₂ W No10⁻⁸ or less No good example with glass (FIG. 8) 71 Example Composition1 Composition 1 Composition 1 Contact N₂ W-1 No 10⁻⁸ or less Good withglass (FIG. 8) 72 Example Composition 1 Composition 1 Composition 1Contact N₂ W-1 100 g/cm² 10⁻⁸ or less Good with glass (FIG. 8) 73Example Composition 1 Composition 1 Composition 1 Contact N₂ W-2 No 10⁻⁸or less Good with glass (FIG. 8) 74 Example Composition 1 Composition 1Composition 1 Contact N₂ W-2 100 g/cm² 10⁻⁸ or less Good with glass(FIG. 8) 75 Example Composition 1 Composition 1 Composition 1 Contact N₂W-3 No 10⁻⁸ or less Good with glass (FIG. 8) 76 Example Composition 1Composition 1 Composition 1 Contact N₂ W-3 100 g/cm² 10⁻⁸ or less Goodwith glass (FIG. 8) 77 Comparative Composition 1 Composition 1Composition 1 Contact N₂ Mo No 10⁻⁸ or less No good example with glass(FIG. 8) 78 Example Composition 1 Composition 1 Composition 1 Contact N₂Mo-1 No 10⁻⁸ or less Good with glass (FIG. 8) 79 Example Composition 1Composition 1 Composition 1 Contact N₂ Mo-1 100 g/cm² 10⁻⁸ or less Goodwith glass (FIG. 8) 80 Example Composition 1 Composition 1 Composition 1Contact N₂ Mo-2 No 10⁻⁸ or less Good with glass (FIG. 8) 81 ExampleComposition 1 Composition 1 Composition 1 Contact N₂ Mo-2 100 g/cm² 10⁻⁸or less Good with glass (FIG. 8) 82 Example Composition 1 Composition 1Composition 1 Contact N₂ Mo-3 No 10⁻⁸ or less Good with glass (FIG. 8)83 Example Composition 1 Composition 1 Composition 1 Contact N₂ Mo-3 100g/cm² 10⁻⁸ or less Good with glass (FIG. 8) 84 Comparative Composition 1Composition 1 Composition 1 Contact N₂ Cu—W No 10⁻⁸ or less No goodexample with glass (FIG. 8)

TABLE VIII Material Oxidation Material for Material for for resistanceSample Material for tubular sealing Sealing electrode Load for Leak rate(750° C. in No. Type ceramic body member member Sealing atmosphere linesealing (Pa · m³/s) the air) 85 Example Composition 1 Composition 1Composition 1 Contact N₂ Cu—W-1 No 10⁻⁸ or Good with glass less (FIG. 8)86 Example Composition 1 Composition 1 Composition 1 Contact N₂ Cu—W-1100 g/cm² 10⁻⁸ or Good with glass less (FIG. 8) 87 Example Composition 1Composition 1 Composition 1 Contact N₂ Cu—W-2 No 10⁻⁸ or Good with glassless (FIG. 8) 88 Example Composition 1 Composition 1 Composition 1Contact N₂ Cu—W-2 100 g/cm² 10⁻⁸ or Good with glass less (FIG. 8) 89Example Composition 1 Composition 1 Composition 1 Contact N₂ Cu—W-3 No10⁻⁸ or Good with glass less (FIG. 8) 90 Example Composition 1Composition 1 Composition 1 Contact N₂ Cu—W-3 100 g/cm² 10⁻⁸ or Goodwith glass less (FIG. 8) 91 Comparative Composition 1 Composition 1Composition 1 Contact N₂ Cu—Mo No 10⁻⁸ or No good example with glassless (FIG. 8) 92 Example Composition 1 Composition 1 Composition 1Contact N₂ Cu—Mo-1 No 10⁻⁸ or Good with glass less (FIG. 8) 93 ExampleComposition 1 Composition 1 Composition 1 Contact N₂ Cu—Mo-1 100 g/cm²10⁻⁸ or Good with glass less (FIG. 8) 94 Example Composition 1Composition 1 Composition 1 Contact N₂ Cu—Mo-2 No 10⁻⁸ or Good withglass less (FIG. 8) 95 Example Composition 1 Composition 1 Composition 1Contact N₂ Cu—Mo-2 100 g/cm² 10⁻⁸ or Good with glass less (FIG. 8) 96Example Composition 1 Composition 1 Composition 1 Contact N₂ Cu—Mo-3 No10⁻⁸ or Good with glass less (FIG. 8) 97 Example Composition 1Composition 1 Composition 1 Contact N₂ Cu—Mo-3 100 g/m² 10⁻⁸ or Goodwith glass less (FIG. 8) 98 Example Composition 1 Composition 1Composition 1 Contact N₂ Kovar 100 g/cm² 10⁻⁸ or Good with glass less(FIG. 8) 99 Example Composition 1 Composition 1 Composition 1 ContactArgon Kovar No 10⁻⁸ or Good with glass less (FIG. 8) 100 ExampleComposition 1 Composition 1 Composition 1 Contact Argon Kovar 100 g/cm²10⁻⁸ or Good with glass less (FIG. 8)

TABLE IX Material Oxidation Material for Material for Material for forLoad resistance ceramic tubular sealing Sealing electrode for Leak rate(750° C. in Sample No. Type body member member Sealing atmosphere linesealing (Pa · m³/s) the air) 101 Example Composition 1 Composition 1Composition 1 Contact Vacuum Kovar No 10⁻⁸ or Good with less glass (FIG.8) 102 Example Composition 1 Composition 1 Composition 2 Contact N₂Kovar No 10⁻⁸ or Good with less glass (FIG. 8) 103 Example Composition 1Composition 1 Composition 4 Contact N₂ Kovar No 10⁻⁸ or Good with lessglass (FIG. 8) 104 Example Composition 2 Composition 2 Composition 1Contact N₂ Kovar No 10⁻⁸ or Good with less glass (FIG. 8) 105 ExampleComposition 3 Composition 3 Composition 3 Contact N₂ Kovar No 10⁻⁸ orGood with less glass (FIG. 8) 106 Comparative Composition 3 Composition3 Composition 1 Contact N₂ Kovar No Not example with sealable glass(Glass (FIG. 8) breakage) 107 Example Composition 1 Composition 2Composition 4 Contact N₂ Kovar No 10⁻⁸ or Good with less glass (FIG. 8)

In the column “material for electrode line” in the tables, Cu—W means acopper (Cu)-tungsten (W) alloy. In the column “material for electrodeline” in Table V, “W-1” for sample No. 38 means that the electrode linewas made of tungsten (W) base material having a nickel (Ni) platinglayer of 2 μm thick (hereinafter referred to as “first plating layer”).“W-2” for sample No. 39 in the column “material for electrode line”means that a tungsten (W) base material having a gold (Au) plating layerof 1 μm thick (hereinafter referred to as “second plating layer”) as acoating layer was used for the electrode line. “W-3” for sample No. 40in the column “material for electrode line” means that a tungsten (W)base material having a nickel (Ni) layer of 2 μm thick and a gold (Au)layer of 1 μm thick plated thereon in that order (hereinafter referredto as “third plating layer”) was used for the electrode line.

“Cu—W-1”, “Cu—W-2”, and “Cu—W-3” for sample Nos. 42 to 44 in the column“material for electrode line” mean that the electrode lines were eachmade of a Cu—W alloy base material having a plating of the first,second, and the third plating layers, respectively. “Mo-1” to “Mo-3” forsample Nos. 46 to 48 in the column “material for electrode line” meanthat the electrode lines were each formed of a molybdenum (Mo) basematerial having a plating of the first to the third plating layers,respectively. In the column, “sealing” in Tables VII to IX, the term“contact with glass (FIG. 8)” means that the type of sealing using inthe holder shown in FIG. 8 was employed.

In order to determine heat resistance and oxidation resistance of theholders, each sample was subjected to heat treatment at 750° C. for1,000 hours in the air. Subsequently, each sample was evaluated withrespect to oxidization at the connection portions (power supplyterminals or the like) between the electrode line and the heater circuitor the like by measuring circuit resistance of the heater circuit, etc.after the heat treatment. As a result, it was confirmed that the samplesof the holders formed according to the embodiments of the presentinvention had sufficient oxidation resistance as shown in FIGS. 2 to 9.

Next, in order to determine the airtightness of a sealed portion (aregion surrounded by the ceramic body, the tubular member, and thesealing member) of each sample, a measuring hole 19, which was a holepenetrating from the surface (on which a wafer is to be mounted) of theceramic body to the sealed portion, was formed, as shown in FIGS. 12 and13. For samples having the structure corresponding to that shown inFIGS. 6 and 7 according to the fourth embodiment of the presentinvention, the measuring hole 19 was formed in the sidewall of thesealing member 21 so as to extend to the inside periphery thereof asshown in FIG. 14. For samples (sample Nos. 69 to 107) having thestructure corresponding to that shown in FIG. 8 of the first modifiedexample according to the fourth embodiment of the present invention, inorder to determine the airtightness, a measuring hole, which was a holepenetrating from a surface (on which a wafer is mounted) of the ceramicbody to a sealed portion, was formed. FIGS. 12 to 14 are schematic,cross-sectional views each showing a sample used for the measurement ofthe airtight property. The inside of the sealed region (the regionsurrounded by the tubular member, the sealing member, and the ceramicbody) and the sealed portion (the region surrounded by the sealingmember and the ceramic body) was evacuated in the direction indicated byan arrow 20 through this measuring hole 19 formed by machining, andsubsequently, the leak rate measurement was performed for each sampleusing a helium detector. The results are shown in Tables II to IX. Ascan be seen from Tables II to IX, the sealed region of each sampleaccording to the embodiment of the present invention had a sufficientairtight property.

In addition, sealing portions (a bonding portion between the sealingmember and the terminal-side electrode line, a bonding portion betweenthe sealing member and the ceramic body) were evaluated with respect tothe formation of a meniscus portion between the glass functioning as thebond member and the tubular member, the sealing member, the ceramicbody, or the electrode line. The results are shown in Tables II to VI.As can be seen in Tables II to VI, in every holder sample havingmeniscus portions, the sealed region had a high airtight property.

Concerning sample Nos. 69 to 107, whether a pressure was applied or notduring firing treatment (while sealing is performed) is shown in TablesVII to IX. From Tables VII to IX, it was understood that a sample towhich a pressure was applied during sealing had a higher airtightproperty.

Although not shown in Tables II to IX, molybdenum (Mo) or tungsten (W)was used as a material forming the power supply terminals embedded inthe ceramic body. When molybdenum (Mo) or tungsten (W) was used as thematerial for the power supply terminals, there were no recognizabledifferences in advantage between the materials in particular.

In the column “sealing” in Tables II to VI, “space”, “contact”, and“individual” are shown. The “space” means the structure in which, as inthe case of the first embodiment of the present invention, a space wasformed as a sealed region by the sealing member, the tubular member, andthe ceramic body, since the sealing member and the ceramic body weredisposed apart from each other. The term “contact” means the structurein which, as in the case of the third embodiment of the presentinvention, the sealing member was in contact with the rear surface ofthe ceramic body. In addition, “individual” means the structure inwhich, as in the case of the fourth embodiment of the present invention,individual sealing members were provided for the correspondingconnection portions between the electrical circuits and theterminal-side electrode lines. The term “contact with glass (FIG. 8)”means the structure in which, as in the case of the holder shown in FIG.8, glass was provided only at the ceramic body side of the sealingmember.

The column “sealing atmosphere” shows an atmosphere used in a heattreatment that was performed for bonding and fixing the sealing memberto the electrode line or the tubular member after application of glass.The material shown in the column “material for electrode line” arematerials used for the electrode lines connected to the power supplyterminals for the electrical circuits, such as a heater circuit, theelectrostatic electrode, and the plasma-forming electrode, which wereembedded in the ceramic body.

The embodiments and the examples described above have been disclosed byway of example, and the present invention is not limited thereto. Thespirit and the scope of the present invention are disclosed in theclaims, and in addition, modification thereof may be optionally madewithout departing from the spirit and the scope of the presentinvention.

1-39. (canceled)
 40. A workpiece holder for holding a workpiececomprising: a ceramic body which has an electrical circuit and whichholds the workpiece; a tubular member having an end portion fixed to therear surface of the ceramic body; power supply conductive memberselectrically connected to the electrical circuit at a connection portioninside the tubular member; and sealing members disposed inside thetubular member and fixed to the rear surface of the ceramic body so asto form sealed portions each surrounding the respective connectionportions; wherein the sealing members isolate sealed portions of theconnection portions from an atmosphere surrounding the outer peripheryof the sealing member.
 41. A processing apparatus provided with aworkpiece holder according to claim
 40. 42. A semiconductormanufacturing apparatus provided with a workpiece holder according toclaim
 40. 43. A workpiece holder according to claim 40, wherein thetubular member and the sealing member are bonded together through abonding member provided therebetween.